In recent years, message display terminals capable of receiving content (e.g. Web page) existing on the Internet are widely used. Advertisement delivery of the push type, employing such message display terminals, is attracting increasing attention today as a new advertising method.
Advertisement delivery systems that deliver advertisements by such a method include, for example, systems described in Japanese Patent Provisional Publication No. 2001-43282 (patent document #1) and Japanese Patent Provisional Publication No. 2002-64560 (patent document #2). In the techniques of the above documents, communication between a mobile terminal (as the message display terminal) and a base station is executed by wireless packet communication, while a gateway is placed between the base station and a content server on the Internet. The gateway server receiving an HTTP request message from the base station executes a protocol conversion (into TCP/IP) to the received HTTP request message, and sends the converted message to the content server. An HTTP response message including content is sent to the base station and to the mobile terminal via the gateway server in a similar manner. By such protocol conversion between the Internet and the packet communication network for the mobile terminals, the browsing of Internet content on the mobile terminals is made possible.
Each of the advertisement delivery systems disclosed in the above documents employs a gateway. Specifically, an advertisement is displayed on the screen of a mobile terminal by adding the advertisement to content data which is transmitted from a content server on the Internet. Such advertisements are the so-called “banner advertisements”. In a character string or an image (hereinafter collectively called a “banner”) placed at the front end (or rear end) of the content data, an anchor for a hyperlink to a resource existing on the Internet is set. Such resources generally include detailed advertisements and online shopping sites. The user of a mobile terminal can let the mobile terminal display such a resource (represented by a hyperlink set in a banner) on its screen by properly operating the mobile terminal.